Go buy a $7 bottle of Fuel Injector Cleaner from the Parts Department at Northland Dodge. You may also want to try some methylhydrate or gas-line antifreeze. People often mistake water in the fuel for faulty injectors because the symptoms can be similar. For you, doing anything to your injector(s) or fuel pump would probably be more expensive than you want to think about right now, I’d try “liquid mechanic” solutions first. Definitely think about replacing your fuel filter, as well. On most Chevy cars, it’s really easy.
When you say 5000rpm, I have to assume that you mean 500rpm… 500 should be about idle, whereas 5000 would be revving it pretty good. So, you could have a problem with your idle-air-control motor or valve. It’s a little device (probably controlled by a little rubber vacuum hose on your car, check to make sure that all of the little hoses hanging around the top of your engine are plugged in to things). You’re also going to want to check your spark plugs, and definitely your air filter.
Does your check engine light ever come on?